Inverse time-limit relay.



PATENTED SEPT. 1, 1908.

I P. BENDMANN. INVERSE TIME LIMIT RELAY.

APPLICATION FILED JAN. 18, 1907.

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UNITED srATEs PATENT. ent ies.

I PETER BENDMANN, OF BERLIN, GERMANY, ASSIGNOR TOGENERAL A CORPORATION OF I that in devices of NEW YORK.

mvnnsn rum-mun RELAY.

To whom may concern:

Be it known that I, PETER BENDMANN, a subject of the Emperor of Germany and-King of Prussia, residing at Berlin, Germany, have invented certaln'new and useful Improvementsin Inverse Time-Limit .Relays, of which the following is a'specification.

This invention relates to electromagnetic controllin devices 'for electric circuits operated by abnormal. currents in be controlled, and more particularly to devices which open the circuit instantaneously in case of an excessive abnormal current or of severe overload upon the circuit, but which do not open the circuituntil after a lapse of a definite interval of time in case the abnormal current is only moderate in amount, or in case the overload is not severe. Devices of this character have been used having an armature restrained by a retarding device, or by a retarding device and an adjustable calibrating spring. The amount of current causing the movement of the armature is varied by altering the tension of the spring or chan 'ng the adjustment of the retardin device, Elli the armature does not move until the current has attained such a stren th that the pull upon the armature is su cientl reat to overcome the resistance of the callrating spring. In case of a severe overload, the armature is strongly attracted, overcoming the tension of the calibrating spring and moving rapidly against the resistance of the retarding device. It is apparent, however, this construction the amountof current causing a comparatively uick opening of the circuit, depends upon the adjustment of the calibrating spring and of the retarding device, which in turn is de termined by the amount of moderate overload at which it is desired to have the circuit open. It is desirable in devices of this class to have the adjustment for moderate overload unafiected by and independent of the ad'ustment for excessive overload.

he object of my invention is to provide a mechanism of this class which is simple in construction and provided with adjusting means to vary the amount of current required to cause the instantaneous operation of the device without affecting the adjustment which determines the amount of current which is required to flow for a definite time interval before the circuit is opened;

Specification of Letters Patent. Application filed January 18,1907. sum No. 352,952.

the circuit to- ,controlling t Patented se tl 1, 1908.

'vary the time which elapses between the oc currence of a moderate overload and the tripping of the circuit-breaker without affectm the other adjustments of the device.

- yinvention consists of an electromagnet, file excitation of which varies as the current in the circuit to be controlled, an armature for themagnet, a member moved by the armature to open the circuit, and means for e rate of movement of the armature connectin the armature and the member, so that the first part of the movement of the armature takes place against the resistance of the oontrollin means only, while during the latter part 0 its movement, when close to the electromagnet where the pullupon the armature is great, the armature moves the member to open the circuit. The initial movement of the armature, therefore, takes place against the resistance of the retarding means only, and the member is not moved by the armature until it is in the most effective relation to the electromagnet. If a ver great pull is exerted upon the armature, su clent force is transmitted to the member through the retarding means to move the member and 0 en the circuit before the retiiiding means as time to act. An adjusta be added to the armature so that the amount of current required to cause the initial movement of the armature may be varied, and an adjustable restraining means may be attached to the member so that the amount of force required to. move the member to open the circuit may be altered.

My invention also consists more specifically of an electromagnet, an armature moved by said magnet upon the occurrence of abnormal current or excessive overload to open the circuit, a second armature also moved to open the circuit by the same electromagnet upon the occurrence of a moderate abnormal current, and means for controlling the rate of movement of the second armature so that the time between the occurrence of a moderate overload and the tripping of the circuitbreaker may be varied.

Myinvention furthermore comprises means whereby the resistance of each armature to the pull of the electromagnet may be varied Without afi'ecting the adjustment of the other armature.

My invention also consists' in mounting and also provided with adjusting means to I one armature upon the other, the armatures ELECTRIC COMPANY,

e restraining means, such as a spring, may

i The invention will best be understood by reference to the accompanying drawings, in which 0 l Figure 1 is a side view of a t1me-l 1nnt relay cmbodyi my invention; and Fig. 2 1s a plan view of t e relay shown n Fig. 1.

The invention is shown in the drawings in the form of a relay having a framework consisting of a vertical member '1 and a horizontal member 2,-these members being formed of iron or similar magnetic material. On the end of the member 2 is supported an electromagnet 3 which is so connected to the circuit which is to be controlled that the flux fiowing through the core of said magnet and through the members 1 and 2 varies with the amount of current in said circuit. A movable member 4 is pivotally mounted at the upper end of the vertical member 1, and on this member is pivotally mounted an armature 5. The movable member 4 may be made of magnetic material, in which case it also acts as an armature, and with armature 5, together with the core of the electromagnet and the members 1 and 2 of the frame, a magnetic circuit is formed which is almost closed. One end of a spiral spring 6 is secured to a lug upon the armature 5, the other end being secured to a bolt 7 upon which is threaded an adjusting nut 8 engaging a bracket 9 carried by the member 4. By means of the bolt 7 and the nut 8, the tension of the spring 6 may be varied, thereby altering the amount of force which is required to cause the initial movement of the armature 5 toward the electromagnet 3. A wing 10 in the form of a portion of a gear-wheel and having teeth upon the rim thereof, is secured to the armature 5, the teeth engaging with a pinion 11 keyed to a shaft 12 rotatably mounted upon the member 4. To one end of the shaft 12 is secured a disk 13 having a number of holes 14 near the circumference thereof. A pin. 15 inserted in one of the holes 14 carries a retarding device 16, for 50 controlling the rate of movement of the armature 5, shown in the form of a dash-pot, but which may be any similar device which will accomplish the same purpose. As shown in the drawing, the dash- 0t 16 is carried upon the pin 15 and the PlStOIl of the dashpot is secured to a pin 17 carried by the member 4. The movement of the armature 5 toward the electromagnet 3 about its pivot causes a movement of the wing 10, and a 50 rotation of the pinion 11 and disk 13. This movement is resisted by the dash-pot 16 and the rate of movement depends upon the degree of vacuum caused in the dash-pot by a given movement of armature 5. The resist- 55 ance which the dash-pot opposes to the movement of'the armature 5' may be varied by inserting the pin 15in different holes 14" in the disk 13, since, ifthe pin is in the hole nearest the dash-pot'when the armature 5 begins to move, the armature can move through nearly its entire travel before the vacuum produced in the dash-pot is enough to seriously retard the movement.

On the up or end of the member 1 is mounted a pate 18, preferably of fiber or similar insulating material, carrying contacts 19 and 20. A bridging contact 21'co6perates with the contacts 19 and 20--and when in engagement therewith, closes the circuit of the trip-coil of the circuit-breaker or similar de- 30 vice b means of which the circuit to be controlle is o ened. A calibrating spring 22 has one en 7 attached to the member .4 and the other end to a bolt 23 carrying an adjusting nut 24 sup orted by abracket 25. By means of the a justing nut 24 the tension of the s ring 22 ma be altered, thereby altering t e amount 0 force required to move the member 4, and the amount of current in the main circuit required to cause that circuit to open instantaneously. It will be observed that the s ring 22 may be calibrated entirely indepen ently of the spring 6, and that the adjustment of one of t ese springs does not in any way affect the adjustment of the other.

The operation of the device is as follows: When an abnormal current of mpderate amount flows in the main circuit, the electromagnet 3 is energized sufliciently to move the armature 5 against the tension of. the spring 6, the armature 5 therefore approaching the electromagnet 3 at a rate which depends upon the adjustment of the dash- 0t 16. As the armature 5 approaches the e ectromagnet 3, the force exerted upon it becomes greater and the magnetic circuit be comes more nearly closed. As the armature nears the .end of its travel, the shoulder 5 engages a corresponding shoulder upon the member 4 whereby the armature and member are locked together, and when the armature 5 is in this osition, the pull of the elec- I tromagnet 3, alt ou h due only to a moderate overload upon t e circuit, is sufiiciently great to move the member 4 against the tension of the spring 22, thereby bringing the bridging contact 21 into engagement with the contacts 19 and 20, closing the circuit of the trip-coil of the circuit-breaker and thereby 0 ening the main circuit. If, however, an a normal current of excessive amount, due to excessive overload, flows in the main circuit, the pull exerted by the electromagnet 3 upon the armature 5 is sufiiciently great when transmitted through the retarding device 16 to cause the member 4 to overcome the spring 22 and instantaneously move toward the electromagnet 3, closing the trip-' circuit and opening the main circuit, al-

by Letters 1. In a circuit-controlling device, the comthough under these conditions armature 5 does not have time to move to the end of its travel and lock with the member 4 before the main circuit is opened. When the member 4 is made of iron or similar magnetic material, it also acts as an armature, and when an excessive abnormal current occurs the instantaneous 0 ening of the circuit is due to the pull of tl ie electromagnet 3 upon the armature 4 as well as upon the armature 5, the pull upon the two armatures quickly overpowering the spring 22.

It is a parent that my invention may be embodie in many other forms than that shown on the purpose of illustration, and I, therefore, do not wish to be restricted to the form of embodiment of my invention shown and de scribed, but intend to cover by the claims all changes and modifications which are within the spirit and scope of my invention.

What I claim as new and desire to secure Patent of the United States, is,

bination with means for establishing a magnetic field, of an armature, a member moved by said armature near the end of its travel to open the circuit, and means connecting said member and said armature for controlling the rate of movement of the armature.

2. In a circuit-controlling device, the combination with an electromagnet, of an armature, a member moved by said armature near the end of its travel to open the circuit, an

adjustable restraining means for said memher, and means connecting said member and sald armature for controlling the rate of movement of the armature.

3. In a circuit-controlling device, the comblnatlon with an electromagnet, of an armature, a member moved by said armature near I the end'of its travel to open the circuit, ad-

justable restraining means for said armature,

and means connectin said member and said,

armature for contro ment of the armature.

4. In a circuit-controlling device, the comelectromagnet, of an arma ture actuated thereby upon excessive abnormal current to break the circuit, a second armature actuated by said electromagnet on moderate abnormal current and moving the first armature .toopen the circuit near the end of its travel, and means to control the rate of movement of the second armature.

5. In a circuit-controlling device, the combination with an electromagnet, of an armature moved thereby to open the circuit on excessive overload, a second armature moved thereby on moderate overload, means fol connecting said second armature near the end of its travel to the first armature to move it and open the circuit, and a retardin deg the rate of movevice to control the rate of movement 0 said second armature.

the drawings which is, merely for 6. In a circuit-controlling device, the combination with an ture moved thereby to open the circuit upon excessive abnormal current, adjustable restraining means for said armature, a second armature moved thereby upon moderate abnormal current and moving the other arma ture to 0 en the circuit near the end of its travel, adjustable restraining means for said second armature, and a retarding device for controlling the rate of movement ofsaid second armature.

7. In a circuit-controlling device, the combination with an electromagnet, of an armature moved thereb to open the circuit upon excessive abnorma current in the circuit, a second armature moved thereby upon moderate abnormal current and moving the other armature near the end of its travel to open the circuit, and means connecting said armatures to control the rate of movement of the first armature.

electromagnet, of an arma-.

8. In a circuit-controlling device, the combination with an electromagnet having an approximately closed magnetic circuit, of an armature forming part of said magnetic circuit moved by said electromagnet upon e x-- cessive overload to open the electric circuit,

a second armature forming part of said magnetic circuit and moved by said electromagnet upon moderate overload to engage said first armature near the end of its travel to move said first armature to open the circuit, and means for controlling the rate of movement of said second armature.

9. In a circuit-controlling device, the combination with an electromagnet, of a pivoted armature moved thereby upon excessive overload to open the circuit, a second armature moved by said electromagnet upon overload ivoted to the first and locked thereto near t e end of its travel, thereby moving the first armature and ope the circuit, and a retarding means to contro the rate of movement of said second armature.

' 10. In a circuit-controlling device, the combination with an electromagnet included in said circuit, .of a pivoted armature moved by excessive overload, adjustable restraining means therefor, a second armature pivoted to the first and moved by moderate overload upon the circuit, a stop upon said first armature engaged by the second armature near the end of its travel, whereby the first armature is moved to open the circuit, and a time- 'hmlt device connecting said armatures for controlling the rate of movement of said first armature.

In witness whereof, I have hereunto set my hand this 31st day of December, 1906.

PETER BEN'DMANNQ Witnesses JULIUs RUMLAND, KARL Kmonznmv. 

